Card printer



July 8, 1969 P. J. lcENBlcE, .JR ET AL 3,454,956

GARD PRINTER Filed Jan. 1a, 196e csheet of 2 To voLTAGE souQce PAI/ME45J; {CENE/CE, J7?.

July 8, 1969 P. J; |CENBICE, JR., ET AL 3,454,955

CARD PRINTER Filed Jan. 18, 1968 5.6 uw we r/IOS IN G /0/ 6.45 VQ P||5\1oe L uw *j* loo United States Patent O 3,454,956 CARD PRINTERPhineas J. Icenbce, Jr., and .Ianck Rooklyn, Altadena,

Calif.; said Rooklyn assignor to Republic Corporation,

Beverly Hills, Calif., a corporation of California Filed Jan. 18, 1968,Ser. No. 698,872 Int. Cl. G01d 15/20; B41j 9/38; H01f 7/08 U.S. Cl.346-104 15 Claims ABSTRACT OF THE DISCLOSURE Card printing apparatuscomprising a multiplicity of closely spaced, rod-shaped plungers whichcan be individually activated so that their marking ends strike a ribbonagainst the card to mark it. Each plunger is a permanent magnet, andeach is propelled by a separate pair of solenoids facing the oppositeends of the plunger. The solenoids are energized so one magneticallyattracts while the other magnetically repels the plunger to move ittoward the card or to move it back from the card. The plungers arearranged so that the marking ends of adjacent plungers are of oppositemagnetic polarity to assure that the plungers move separately.

Background of the invention This invention relates to printing apparatusand, more particularly, to apparatus wherein a marking mechanism ismoved toward the material to be marked.

In many printing applications, it is necessary to independently actuatea number of closely spaced printing mechanisms. One such application isin certain telephone billing apparatus, wherein a card is positioned ina printer and the ten digit number which has been called is recorded byprinting ten dots on the card. The printing apparatus includes 100plungers and requires 100 separate plunger operating mechanisms.Relatively small cards, such as standard IBM cards which are 3% inches4by 75A@ inches are used, and therefore the plungers must be closelyspaced, for example, at quarter-inch centers.

In the foregoing billing apparatus, an inked ribbon is utilized to printthe dots, and a dot is printed when a plunger strikes the ribbon.Mechanisms used heretofore for moving plungers generally included aplunger of soft iron extending through the core area of a solenoid.Energization of the solenoid moved the plunger in one direction and aspring returned the plunger when the solenoid was de-energized. In orderto move the plunger rapidly to assure clear printing, a large solenoidwas used. However, such large solenoids cannot lit in the small spaceavailable when large numbers of plungers must be positioned closetogether.

The construction of a narrow-diameter plunger can be accomplished usingthe conventional plunger which moves within a hollow solenoid, by usinga very long solenoid and activating it with large currents. However,resort to such measures is limited by heating, space limitations, andthe greatly increased costs which they give rise to. An efficientmechanism for the independent activation of a large number of closelyspaced solenoids, which moved the plungers with sucient force to provideclear printing, would be useful in card printing mechanisms and avariety of other applications.

Summary of the invention Accordingly, one object of the presentinvention is to provide economical printing apparatus for marking cardsat any of a large number of closely spaced locations.

Another object is to provide a plunger activating mechanism whichoccupies a smaller space than those available heretofore.

lIn accordance with the present invention, there is provided a cardprinter comprising a multiplicity of closely spaced plungers, which canbe independently moved toward the card to mark it. Each plunger is apermanent magnet, and is moved -by a solenoid which attracts or repelsit to move it toward or away from the card. A marklng end of the plungerstrikes a ribbon and presses it against the card to print a charactersuch as a dot on the card.

Each plunger has the shape of a rod and is constructed of permanentmagnet material, with its marking end and back end of opposite magneticpolarity. The plunger is held in a tube of non-magnetic material, whichguides it 1n sliding toward and away from the card. A separate pair ofelectro-magnets, or solenoids, is provided to move each of the plungers.One solenoid is located on the side ofthe card opposite the front ormarking end of the plunger, and the other solenoid is located oppositethe rear end of the plunger. The two solenoids are simultaneouslyenergized, so that when energizing currents flow in one direction, onesolenoid pulls the plunger and the other pushes it toward the card. Whencurrents flow through the solenoids in the opposite direction, onesolenoid pushes the plunger away from the card while the other solenoidpulls it away.

The matrix of closely spaced plungers is arranged so that the markingends of adjacent plungers are of opposite magnetic polarity. It has beenfound that this prevents a group of plungers from moving together whenthe solenoids of only one of them has been energized.

Each pair of solenoids can be constructed with a small diameter andmoderate length. Yet, with even moderate currents, the solenoids movethe plunger with considerable force to provide clear printing. Thepermanent magnet construction of the plunger provides a high strengthmagnetic field in a small space. The magnetic field is considerablygreater than ordinarily can be achieved by an electromagnet of the samesize, with the heat dissipation limitations encountered. The pair ofsolenoids provides two moderate strength magnetic fields for interactingwith the strong permanent magnet tield of the plunger, to propel theplunger with considerable force.

The novel features of the invention are set forth with particularity inthe appended claims. The invention will best be understood from thefollowing description when read in conjunction with the accompanyingdrawings.

Brief description of the drawings FIGURE l is a perspective view of acard printer constructed in accordance with the invention;

FIGURE 2 is a sectional View of a portion of the card printer of FIGUREl;

FIGURE 3 is a fragmentary sectional view of the card printer of FIGUREl;

FIGURE 4 is an elevation view of the card printer taken on-.the line 4-4of FIGURE 3; and

FIGURE 5 is a schematic diagram of a circuit for supplying energizingcurrents to the card printer.

Description of the preferred embodiments FIGURE l illustrates a cardprinter constructed in accordance with the invention, the card printercomprising a housing 10, having a slot 12 for receiving the end of acard 14. The card 14 has a printing area 1:6 thereon divided into smallboxes. After the ca-rd is inserted into the card printer 10, ten dotsare printed on the printing area to indicate the ten digits of a numberwhich has been called by a telephone subscriber. Each dot is printed bya separate printing mechanism, and the card printer contains 100 suchmechanisms. The printing is accomplished by plungers within the housingwhich strike a ribbon 24 that lies in front of the card. The ribbonmoves between rollers 13 and '15 mounted on the housing. The plungersare held in a plunger plate 22 of the housing, and are moved bysolenoids held in a front solenoid plate 18 and rear solenoid plate 20of the housing.

FIGURE 2 illustrates a portion of the printing apparatus of IFIGURE l,showing several of the mechanisms, each of which can print one dot onthe card. The printing apparatus comprises the front solenoid plate 18,the rear solenoid plate 20, and the plunger plate 22, which is locatedbetween the two solenoid plates. Each of the three plates has 100 holesarranged in ten columns and ten rows, and corresponding holes in thethree plates are aligned with each other. The card receiving slot 12lies between the front solenoid plate 18 and the plunger plate 22. Aportion of the ribbon 24 is positioned in the slot adjacent to theplunger plate 22 and is held taut by the ribbon rollers. The spacebetween the ribbon 24 and solenoid plate 18 is adapted to receive a card14 on which information is to be printed.

A dot is printed on the card 14 when a plunger 46 strikes the ribbon 24,moving it against the card 14. Each plunger is essentially a permanentbar magnet with a front or marking end -50 of one magnetic polarity anda rear end 48 of the other magnetic polarity. The plunger 46 ispropelled toward and away from the card by a pair of solenoids. A frontsolenoid 26 is positioned near and in opposed relation to the markingend 50 of the plunger, while a rear solenoid 36 is positioned adjacentto and in opposed relation to .the rear end `48 of the plunger. When thesolenoids are energized with currents in one direction, they both movethe plunger toward the card, the front solenoid 26 pulling it bymagnetic attraction and the rear solenoid 36 pushing it by magneticrepulsion. Reversal of currents in the solenoids moves the plunger awayfrom the card.

YA detailed description of the apparatus will be given below.

A separate front solenoid 26 is positioned in each hole of the frontsolenoid plate 18. Each front solenoid comprises a core 28 constructedof a narrow rod portion 30 and a wide face portion 32. The face portion32 faces the slot 12, while the narrow rod portion 30 extends along thelength of the hole. A solenoid winding 34, comprising multiple turns ofan electrical conductor, is disposed about the rod portion 30. The rearsolenoid plate 20, located at the rear end of the plungers, is similarlyconstructed, with a rear solenoid 36 in each of its holes. Each rearsolenoid similarly comprises a core 38 with a rod portion 40` extendingalong its length and a face portion 42 facing the plunger plate 22. Arear solenoid winding 44 is wound about the rod portion 40.

A plunger 46 is disposed in each hole of the plunger plate 22. IEachplunger is a cylindrical rod constructed of permanent magnet material,such as Alnico, and functions like a bar magnet. The rear end 48 of eachplunger is positioned adjacent to the face portion of a rear solenoid,while the front or marking end 50 is positioned adjacent to the ribbon24. The marking end 50 is tapered to an almost flat tip, which contactsa small round area of the ribbon. The solenoid 36 has a. lengthapproximately equal to the width W of the plunger plate 22 within whichit moves, so it travels a small distance before contacting the ribbon.The magnetic polarities of the plunger ends are indicated by the N and Ssigns designating the north and south poles, respectively.

Each of the two hundred solenoid windings has two terminals, a `first ofwhich may be grounded, as by connection to a common grounding wire. Thesecond terminal, such as terminal 54 of the solenoid 26, is connected tothe second terminal 58 of the rear solenoid 36 with which it is aligned.Both terminals are connected to a contact 62 of a selecting switch 64.The other contact of the switch is connected to a common conductor 66which carries currents from a common switch 80` to energize thesolenoids. If any of the selecting switches, such as switch 64, is in aclosed position at a time when there is a voltage on the 'conductor 66,both the front and rear solenoids which are aligned with one of theplungers are energized.

The front and rear solenoid windings of each plunger are connected sothat, when they are energized, their core face portions 32 and 42 havethe same magnetic polarity. Both of the solenoids will tend to move theplunger 32 in one direction. The plunger will move toward the frontsolenoid or toward the rear solenoid, depending upon the direction ofcurrent from the common conductor 66. For example, if the current at anyinstant is in a direction which makes the face portions 32 and 42 of thesolenoids magnetically north, then the plunger 46 will move toward thefront solenoid. This occurs partly because the marking end 50 of plunger46 is magnetically south and. is attracted by the north pole of the coreface portion 32. Additionally, the rear end 48 of the plunger is a northpole and is repelled by the north pole at the face of the rear solenoid36.

The combined pulling and pushing action of the front and rear solenoidsmoves the plunger with considerable force to provide clear markings. Alarge force is obtained because a small permanent magnet plunger of highiield strength can be obtained by using Alnico or other good permanentmagnet material. Magnetic attraction is generally proportional to theproduct of the field strength of interacting magnetic poles, so highforces are produced with only moderate strength solenoids.

FIGURE 4 illustrates the plunger plate 22 and the matrix of one hundredplungers therein. The gure also shows the slots 72 and 74 through whichthe ribbon moves. As shown in the figure, the plungers are arranged sothat the marking end of adjacent plungers are of opposite polarity. Forexample, the plunger 46 has a marking end of south polarity, and theplungers on either side of it in the same column or same row have northpolarities. The arrangement of north and south pole marking endsinterspersed with each other has been found to be generally necessary toprevent adjacent plungers from moving when the pair of solenoids of onlyone of them has been activated. It might be supposed that all solenoidsshould be arranged with their marking ends of the same polarity.However, it has been found that the plungers move together when such anarrangement is used. As a byproduct of the arrangement of adjacentplungers with opposite polarities, the plungers do not readily losemagnetic strength because lines of magnetic force from a pole of oneplunger have a short path before entering an opposite pole.

The illustrated card printer is used by an operator who causes ten outof the one hundred selecting switches of the type shown at 64 in FIGURE2 to be closed. One selecting switch is closed as each digit of a l0digit number is dialed. When all ten digits have been dialed, and thecall has been completed, the operator inserts a card into the slot ofthe card printer and closes a switch 76 shown in FIGURE 2. Closing ofthe switch 76 activates a relay control apparatus 78. The relay controlapparatus 78 controls a relay 79 to operate the common switch 80. Theswitch 80 is thrown from a neutral position into contact with positiveterminal 82, then into contact with negative terminal 84, and then backto a neutral position. The positive terminal 82 is connected to apositive voltage source, while the negative terminal 84 is connected toa negative voltage source, as by connecting a battery between them.

When the switch 80 contacts the terminals 82 and 84, currents ow throughthe ten pairs of solenoids whose selecting switches have been closed. Atthe time that the switch 80 contacts positive terminal 82, currents flowthrough the -ten pairs of solenoids in directions which move theirplungers toward the card, thereby marking the card. When the switchcontacts negative terminal 84, the currents flow in the oppositedirection and the ten plungers move away from the card to their rearwardposition. While a single thrust makes a relatively dark mark. markingclarity is increased if each plunger strikes the ribbon several timesfor each mark. This is accomplished by providing a relay apparatus 78which operates the relay 79 to alternate the switch 80 several timesbetween the positive and negative terminals 82 and 84. The switch 80should always contact the negative terminal 84 before nally moving to aneutral position. This assures that the plungers will end in a rearwardposition. The plungers maintain this position when current is thereafterremoved, by reason of magnetic attraction with the soft ironface of therear solenoid. A weak spring return could be used to move the plungerback, instead of reversing the solenoid currents, but the cost ofproviding circuits to reverse the currents is generally lower than thecost of one hundred additional springs and the provisions required tohold them in place.

The relay apparatus 78 can be constructed in a number of ways well knownin the art. For example, it can include pulse generating circuitry togenerate a pulse having .well defined leading and trailing edges eachtime the switch 76 is closed. The leading edge can be used to move the.switch 80 to the positive terminal 82 while the trailing edge can beused to move the switch to the negative terminal 84. To move theplungers back and forth several times, a ringing circuit or the like canbe provided to generate several spaced signals to operate the pulsegenerating circuitry each time the switch 76 is closed. The selectingswitches, such as switch 64, should be opened prior to the dialing ofthe next telephone number to be called, whether or not a card has beenprinted. This can be done by using a relay for closing each selectingswitch, and causing all relays to open their switches when a call iscompleted. Such apparatus is not part of the invention and therefore hasnot been shown.

FIGURE 5 is a detailed view of a circuit for providing currents thatoperate the solenoids and move the printing plungers against a card. Thecircuit has an output 100 for connection to the common conductor 66shown in FIG- URE 2, in place of the circuitry described above. Unlikethe circuit described above, the circuit of FIGURE 5 provides a directcurrent with a waveform shown at 1, which varies rapidly in intensityinstead of varying rapidly n-polarity. As a result, the plungers do notrapidly move back and forth many times but instead move against the cardand are"alternately hammered hard against the card and partiallyreleased. Thereafter, the polarity of the energizing current is reversedand the plungers are returned to their rearward position. It should beunderstood that the circuit of FIGURE 5 is shown with specific componentvalues only as an example, and many other circuits may beused instead.

The circuit of FIGURE 5 comprises an input switch 76 which is closedwhen all 10 digits have been key pulsed or dialed and the operatorinserts a card into the slot of the card printer. Closing of the switch76 causes a trigger circuit 102 to deliver a positive going pulse totransistor Q1, thereby turning it on. Transistor Q1 passes a pulse totransistor Q2, thereby charging capacitor C1. The capacitor C1 thereuponturns off transistor Q3 for -a period such as 350 milliseconds. Thecurrent at junction 104 thereupon rises toward 12 volts and remains atthis level for 350 milliseconds. The pulse at junction 104 is amplifiedby the transistors Q4 and Q5 and transmitted to relay coil 106, to closethe relay contacts 108 for a period of 350 milliseconds. This allows anoutput at 100 to be delivered for a period of 350 milliseconds.

During the 350 millisecond interval when junction 104 is at a highlevel, capacitor C2 is charged. It requires approximately 175milliseconds before the junction 110 rises to a value wherein transistorQ6 is turned on. When Q6 is turned on, transistor Q8 completes a circuitin series with a relay coil 112 and a voltage supply at 115. Whencurrent flows through relay coil 112, relay contact 114 is moved from acontact 116 to a contact 118. During the first 175 milliseconds beforerelay coil 112 is energized,

currents ow from ground G to terminal 116, through relay contact 114,through a transformer coil 120', and through the closed relay contact108 to the output 100. During the second 175 milliseconds, currents flowfrom a source 122 to terminal 118, through contact 114 to the output100. Thus, during the rst 175 milliseconds, a DC voltage with an averagevalue of ground potential G is provided at output while, during thesecond 175 milliseconds, a voltage with an average value L of that atthe junction 124 is provided at the output 100.

An alternating current is impressed on the direct currents at the output100. This is achieved by connecting an alternating current, such as anormal house current of approximately 117 volts to an input of atransformer 126. Thisfvoltage is reduced to a smaller AC voltage acrossthe output coil 120 of the transformer. For a circuit with componentValues shown in FIGURE 5, the potential L at junction 124 is 40 voltsinitially, while a reference voltage VR of 20 volts is provided atjunction 128. For a transformer 126 providing a 6.3 volts root meansquare output across coil 120, the output at 100 during the firstmilliseconds initially rises to 30 volts above` the voltage VR at thereference junction 128. During the second 175 milliseconds, the outputinitially falls to 30 volts below VR. At the end of the 350 millisecondsinterval, the voltage output at 100 is equal to the reference voltageVR. The reference voltage VR is connected to the second input of each ofthe 200 solenoids instead of grounding them.

The apparatus of the invention can be used to print alphanumeric orother characters in addition to the dot characters by using appropriatetype faces on the plungers, and by using a track to prevent plungerrotation. Special papers which are marked by striking them can be usedto record marks without a ribbon. If thin cards and high currents areused, it is even possible to mark the cards by punching holes in them.

What is claimed is:

1. Printing apparatus for printing material received in a predeterminedarea comprising:

an elongated permanent magnet having rst and second ends which aresubstantially magnetic poles;

means supporting said permanent magnet for reciprocation insubstantially linear motion in the direction of its elongation towardand away from said area; and

-a solenoid positioned in opposed relation to said first end of saidpermanent magnet to move it in the direction of its elongation.

2. Printing apparatus as defined in claim 1 including:

a second solenoid positioned in opposed relation to said second end ofsaid permanent magnet; and

means for simultaneously energizing said solenoids to cause eachsolenoid to irnpel said permanent magnet in the same direction.

3. Printing apparatus as defined in claim 1 wherein:

one of said ends of said permanent magnet which is closest to said areain which material is received has a face defining a character to beprinted on said material.

14. Printing `apparatus as defined in claim 1 including:

means coupled to said solenoid for providing a direct current whichvaries in intensity, to vary the force o'f said magnet against materialin said area.

5'. Apparatus for marking material comprising:

means defining an area for receiving material to be marked;

a plunger including a front end for movement toward said area to marksaid material, said plunger constructed of a permanent magnet materialand magnetized;

guiding means for guiding said front end of said plunger in movementtoward and away from said area;

solenoid means positioned adjacent to said plunger for magneticallyinteracting with it to move said front end thereof toward said area; andi energizing means coupled to said solenoid means for energizing it.

6. Apparatus as defined in claim wherein:

said plunger has a rear end opposite said front end, and is magnetizedwith said front and rear ends forming magnetic poles; and

said solenoid means comprises a first solenoid having a solenoid facefacing said rear end of said plunger and a second solenoid having asolenoid face positioned on a side of said area opposite said plungerand facing said front end of said plunger, to interact with the poles atboth ends of said plunger.

7. Apparatus -as defined in claim 6 wherein:

said front and rear ends of said plunger have opposite magneticpolarity; and

said energizing means includes means for simultaneously energizing saidfirst and second solenoids to magnetize said faces of said solenoidswith the same polarity, thereby to simultaneously push and pull saidplunger toward said area.

8. Apparatus as defined in claim 5 wherein:

said plunger is elongated, with a rear end located opposite said frontend, and said front and rear end forming magnetic poles; and

said solenoid means is positioned opposite at least one end of saidplunger for magnetically interacting with it; and including a pluralityof additional plungers constructed of permanent magnet material andhaving lfront and rearends which are magnetic poles, said additionalplungers positioned laterally from each other 'for movement toward andaway from said area;

`a plurality of additional guiding means, each engaged with one of saidplurality of additional plungers for constraining it to movement towardand away from said area;

Ia plurality of additional solenoid means, each positioned opposite anend of each of said additional plungers for magnetically interactingtherewith; and

a plurality of additional means for energizing said plurality ofadditional solenoid means independently of each other for independentlymoving each of said plungers toward said area.

9. Apparatus as defined in claim 8 wherein:

each a plurality of said plungers with a front end of south magneticpolarity is adjacent to a plurality of other plungers having a front endof north magnetic polarity, `whereby to assure movement of only theplungers whose solenoid means are energized.

10. In apparatus including a housing for receiving a card in a card areato mark the card by thrusting a plunger toward the card and against aninked ribbon or other means which causes marking of the card when struckby the plunger, the improvement comprising:

a plunger rod having a marking end facing said card and a rear end, saidrod constructed of a permanent magnet material and magnetized with itsmarking end and rear end of opposite magnetic polarities;

means disposed on said housing for constraining said rod to movementsubstantially toward and away from said card area;

first solenoid means positioned on a side of said card `area oppositesaid marking end of said rod for magnetically interacting with said rodto pull it toward said card area and push it away therefrom;

second solenoid means positioned ladjacent to said rear end of said rodfor magnetically interacting with said rod to push it toward said cardarea and pull it away therefrom; and

5 10 wherein:

said means for energizing comprises means for delivering a current whichreverses direction and is in a direction to move said rod away from saidcard area immediately prior to substantial termination of current.

12. The improvement in apparatus as defined in claim 10` including:

12 wherein:

said multiplicity of plunger rods are arranged substantially in rows andcolumns, and the marking end of each plunger rod has a polarity which isopposite to the polarity of the marking ends of `adjacent plunger rodsin the same row and of adjacent plunger rods in the same column.

14. A card printer comprising:

a housing having a slot for receiving a card to make markings thereon,plunger plate means for holding a plurality of plungers to mark saidcard, front solenoid plate means positioned on a side of said slotopposite said plunger plate means for holding a .plurality of ffrontsolenoids, and rear solenoid plate means positioned on a side of saidsolenoid plate means opposite said slot for holding rear solenoids;

a plurality of permanent magnet plungers disposed in said plunger platemeans for movement toward and away from said slot, each plunger having amarking end for marking a card when the plunger is moved toward saidslot;

a plurality of front solenoids disposed in said front solenoid platemeans, each aligned -With one of said plungers;

a plurality of rear solenoids disposed in said rear solenoid platemeans, each laligned with one of said plungers; and

means coupled to said solenoids for substantially simultaneouslyenergizing a front solenoid and a rear solenoid which are aligned withone of said plungers, with currents in directions which energize onesolenoid to pull said plunger while the other pulls it lby magneticinteraction.

15. A card printer as defined in claim 14 wherein:

a first plurality of said plungers has marking ends of north magneticpolarity and a second plurality of said plungers interspersed 'with saidfirst plurality of plungers has marking ends of south magnetic polarity.

References Cited UNITED STATES PATENTS 3,038,653 6/1962 Jetfords 234-108X 3,281,853 10/1966 Madeira et al 346-141 X RICHARD B. WILKINSON,Primary Examiner.

JOSEPH W. HARTARY, Assistant Examiner.

U.S. C1. X.R.

lOl-93; l79-7.1; 197-53; 234-108; 335-229; 346- 141

